In varnishing work, the varnish can be applied in the form of a full surface or recessed. In the former case blankets are normally used. In the case of varnish applications with simple recesses, a blanket is usually used while a printing plate, e.g. a Nylonprint-Letterset plate, is used for complicated recesses. When ordering a press, the client must decide between a clamping device which is designed either for the satisfactory fixing of a printing plate in the form of an adjustable plate clamping bar, or for the fixing of a blanket in the form of a blanket clamping device.
Unlike a printing plate clamping device, a clamping device to fix a blanket does not permit circumferential and lateral positioning in relation to the print. Unfortunately, a conventional adjustable plate clamping device provided with the said positioning abilities does not allow satisfactory fixing of a blanket. Therefore, the utilization of a printing plate or a blanket in the same blanket clamping device or plate clamping bar presents considerable difficulties.
German Patent No. 1,119,877, discloses a device to clamp a printing plate or a blanket to a press cylinder by means of clamping spindles disposed in the cylinder channel so that different types of printing work can be carried out, e.g. dry offset, wet offset or letterpress printing. However, a disadvantage of this device is that the clamping lugs for a blanket have to be replaced with clamping lugs for a printing plate. Nor is blanket positioning possible because the clamping spindles are not adequately adjustable.